Now that explains why thus particular email that had a score of 3.4 was tagged as it was but I'm now struggling to find out WHY Amavis tagged it with this particular score and I have no idea what RelayedTaggedInbound means as I guess that would be the explanation?

You would have to look at the mail's source code to find this out.
There should be an explanation in the mails source what spam-checks and scores were applied.
It's mostly impossible to see the reason when only looking at the mail log.